1. Field of the Invention
The present invention relates to a method and apparatus for turning on and off a lamp installed in a refrigerator.
2. Description of the Related Art
A refrigerator generally includes a lamp for lighting the inside thereof as for a user to easily distinguish foods stored therein. The lamp is turned on when a door of the refrigerator is opened. Conversely, it is turned off when the door is closed.
A conventional method for turning on and off the lamp according to the state of the door will be described with reference to FIGS. 1 and 2.
FIG. 1 illustrates a conventional lamp turning on and off unit for turning on and off the lamp depending on the open and closed state of the door. As shown, the conventional lamp turning on and off unit includes a microcomputer 1 for performing a predetermined program. The microcomputer 1 is connected to a switch SW that is operated by the door of the refrigerator, and the microcomputer 1 is also connected to a lamp driving unit 2 for turning on and off the lamp L.
Referring to FIG. 2, the lamp L is controlled according to the operation of the switch SW which is turned on when the door of the refrigerator is opened and turned off when the door is closed. In other words the microcomputer 1 makes a determination as to whether the door is opened or closed depending upon a contact signal from the switch SW. When the door is opened, i.e., if it is determined that the switch SW is on, the microcomputer 1 causes the lamp to be turned on by means of the lamp driving unit 2. Otherwise, when the door is closed. i.e., if it is determined that the switch SW is off, the microcomputer 1 causes the lamp to be turned off through the lamp driving, unit 2.
According to the aforementioned conventional method, the switch SW is actually turned on when the door is nearly half opened. Thus some amount of time is delayed for the microcomputer 1 to recognize that the door is opened. Moreover, such a lamp driving unit is generally composed of a relay circuit. Accordingly, another amount of time may be taken for a relay contact point to be operated after the microcomputer 1 commands the lamp to be turned on.
As a result, the user has felt inconvenience in use of the refrigerator because the lamp is not turned on when he opens the door of the refrigerator. In particular, a fluorescent lamp that is more widely used for the refrigerator than a glow lamp also causes a delay. The fluorescent lamp rarely influences temperature in the refrigerator, however requires more time to be illuminated when compared to the glow lamp.